Faber Pencil, Recipe for Success

Having secured supplies of Siberian graphite in the 1850s, Johann Faber advertised the "great purity" of the new material by publishing its chemical analysis. This was Faber's pencil recipe for success:

Carbon...................................................94.5
Kaolin..................................................... 3.1
Silicic acid............................................... 1.6
Oxide of iron........................................... 0.4
Chalk and magnesia................................. 0.2
Foreign matter......................................... 0.2
                                                            100.0

 The Faber Manufacture, ca. 1850. Courtesy of Faber-Castell AG.

Quotes by Henry Petroski, The Pencil. A History of Design and Circumstance. London & Boston 1989